Added running average methods to determine if we should send temperature / humidity reports

libraries/RunningAverage/RunningAverage.cpp

@@ -0,0 +1,101 @@
+//
+//    FILE: RunningAverage.cpp
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.2.08
+//    DATE: 2015-apr-10
+// PURPOSE: RunningAverage library for Arduino
+//
+// The library stores N individual values in a circular buffer,
+// to calculate the running average.
+//
+// HISTORY:
+// 0.1.00 - 2011-01-30 initial version
+// 0.1.01 - 2011-02-28 fixed missing destructor in .h
+// 0.2.00 - 2012-??-?? Yuval Naveh added trimValue (found on web)
+//          http://stromputer.googlecode.com/svn-history/r74/trunk/Arduino/Libraries/RunningAverage/RunningAverage.cpp
+// 0.2.01 - 2012-11-21 refactored
+// 0.2.02 - 2012-12-30 refactored trimValue -> fillValue
+// 0.2.03 - 2013-11-31 getElement
+// 0.2.04 - 2014-07-03 added memory protection
+// 0.2.05 - 2014-12-16 changed float -> double
+// 0.2.06 - 2015-03-07 all size uint8_t
+// 0.2.07 - 2015-03-16 added getMin() and getMax() functions (Eric Mulder)
+// 0.2.08 - 2015-04-10 refactored getMin() and getMax() implementation
+//
+// Released to the public domain
+//
+
+#include "RunningAverage.h"
+#include <stdlib.h>
+
+RunningAverage::RunningAverage(uint8_t size)
+{
+    _size = size;
+    _ar = (double*) malloc(_size * sizeof(double));
+    if (_ar == NULL) _size = 0;
+    clear();
+}
+
+RunningAverage::~RunningAverage()
+{
+    if (_ar != NULL) free(_ar);
+}
+
+// resets all counters
+void RunningAverage::clear()
+{
+    _cnt = 0;
+    _idx = 0;
+    _sum = 0.0;
+    _min = NAN;
+    _max = NAN;
+    for (uint8_t i = 0; i < _size; i++)
+    {
+        _ar[i] = 0.0; // keeps addValue simple
+    }
+}
+
+// adds a new value to the data-set
+void RunningAverage::addValue(double value)
+{
+    if (_ar == NULL) return;  // allocation error
+    _sum -= _ar[_idx];
+    _ar[_idx] = value;
+    _sum += _ar[_idx];
+    _idx++;
+    if (_idx == _size) _idx = 0;  // faster than %
+    // handle min max
+    if (_cnt == 0) _min = _max = value;
+    else if (value < _min) _min = value;
+    else if (value > _max) _max = value;
+    // update count as last otherwise if( _cnt == 0) above will fail
+    if (_cnt < _size) _cnt++;
+}
+
+// returns the average of the data-set added sofar
+double RunningAverage::getAverage()
+{
+    if (_cnt == 0) return NAN;
+    return _sum / _cnt;
+}
+
+// returns the value of an element if exist, NAN otherwise
+double RunningAverage::getElement(uint8_t idx)
+{
+    if (idx >=_cnt ) return NAN;
+    return _ar[idx];
+}
+
+// fill the average with a value
+// the param number determines how often value is added (weight)
+// number should preferably be between 1 and size
+void RunningAverage::fillValue(double value, uint8_t number)
+{
+    clear(); // TODO conditional?  if (clr) clear();
+
+    for (uint8_t i = 0; i < number; i++)
+    {
+        addValue(value);
+    }
+}
+// END OF FILE